From: Joerg Roedel <joro@8bytes.org>
To: Daniel J Blueman <daniel.blueman@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: [2.6.35-rc3] select useful number of entries for DMA debugging...
Date: Sat, 10 Jul 2010 17:43:31 +0200 [thread overview]
Message-ID: <20100710154331.GF10080@8bytes.org> (raw)
In-Reply-To: <AANLkTinLjhLoQJ8URiuCKqgntiLEKxCesNEPZ8b24uLu@mail.gmail.com>
On Sat, Jul 10, 2010 at 03:52:04PM +0100, Daniel J Blueman wrote:
> On 9 July 2010 22:33, Linus Torvalds <torvalds@linux-foundation.org> wrote:
> > On Mon, Jul 5, 2010 at 1:35 AM, Daniel J Blueman
> > <daniel.blueman@gmail.com> wrote:
> >> When booting 2.6.35-rc3 on some different x86 boxes with DMA debugging
> >> enabled, I've consistently seen it exhaust the allocated entries during
> >> boot, giving 'DMA-API: debugging out of memory - disabling'.
> >>
> >> Increase number of entries to allow DMA debugging again.
> >
> > Rather than increase the default that gets allocated whenever anybody
> > enables the DMA debugging, I'd really prefer to see people use the
> > kernel command line option if they run out. After all, it's a (pretty
> > esoteric) debug option, and the number of required entries depends on
> > machine configuration. I'd rather not make the default cover a huge
> > number, when you could just add
> >
> > dma_debug_entries=65536
> >
> > on the kernel boot command line instead for machines that want/need it..
>
> That said, I am seeing the DMA pool exhaust on a single socket Core i5
> system with Intel graphics and no other adapters - seems like a fairly
> common case. If eg 25% of developers will be using similar to this,
> maybe it's good to make DMA debugging less immediately esoteric?
>
> On the other hand, I would immediately agree if the exhaustion
> occurred on an atypical setup.
How much memory do you have in this machine? We could probably make the
number of pre-allocated entries dependent on the memory available in the
machine like Ingo suggested some time ago to avoid such problems.
Joerg
next prev parent reply other threads:[~2010-07-10 15:43 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-05 8:35 [2.6.35-rc3] select useful number of entries for DMA debugging Daniel J Blueman
2010-07-09 21:33 ` Linus Torvalds
2010-07-10 14:52 ` Daniel J Blueman
2010-07-10 15:43 ` Joerg Roedel [this message]
2010-07-11 11:54 ` Daniel J Blueman
2010-07-11 13:00 ` Daniel J Blueman
2010-07-12 14:39 ` John Stoffel
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100710154331.GF10080@8bytes.org \
--to=joro@8bytes.org \
--cc=daniel.blueman@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox